A semiconductor treatment process comprises various steps, such as a step of inspecting the electrical characteristic of a to-be-inspected object (e.g., a semiconductor device) in the state of a wafer, and a step of inspecting a to-be-inspected object in the state of a package. To perform inspection, the electrodes of a wafer are brought into contact with contact elements (e.g., probe pins). A measurement signal is applied to the electrodes via the probe pins. The surfaces of the electrodes of the to-be-inspected object are coated with electrically insulating oxide films. Accordingly, in the prior art, each probe pin is pressed against an electrode, thereby removing part of the oxide film of the electrode and electrically connecting them to each other.
However, in a high-density device formed on a wafer, electrodes and wires formed of thin films are employed. The method for removing the oxide film of each electrode P using corresponding probe pins during inspection of a wafer may well damage each electrode or its ground layer. To prevent such damage, a method for removing the oxide film of each electrode utilizing the fritting phenomenon has been proposed (see patent document 1—Jan. Pat. Appln. KOKAI Publication No. 2002-139542 (claim 1 and section [0046])).
Referring to, for instance, FIG. 2, the technique described in patent document 1 will be roughly described. As shown in FIG. 2, a probe card 1 comprises pairs of probe pins 2 to be brought into contact with respective electrodes P on a wafer, and relays 3 connected to the respective pairs of probe pins 2. The relays 3 switch the connection destination of each pair of probe pins 2 from a tester 4 to a power supply 5 for fritting or vice versa. To inspect the electrical characteristic of the to-be-inspected object on the wafer, firstly, a pair of probe pins 2 is brought into contact with an electrode P. The corresponding relay 3 connects the pair of probe pins 2 to the power supply 5 for fritting. The fritting power supply 5 applies a voltage to one of the pair of probe pins 2, and gradually increases the voltage level. At this time, the fritting phenomenon occurs, thereby breaking the oxide film between the tips of the pair of probe pins 2 to electrically connect the probe pins 2. The relay 3 switches the connection destination of the pair of probe pins 2 from the fritting power supply 5 to the tester 4. The tester 4 applies an inspection signal to the electrode P via one of the probe pins 2 to thereby test the electrical characteristic of the to-be-inspected object. The use of the fritting phenomenon enables the probe pressure between each probe pin 2 and the electrode P to be set extremely low, with the result that the electrodes, for example, are prevented from being damaged, and a highly reliable inspection can be executed. The fritting phenomenon is such a phenomenon as this. When a voltage is applied to an oxide film formed on the surface of a metal (an electrode in the invention), and the potential inclination applied is increased to about 105 to 106V/cm, a current flows to break the oxide film because of non-uniformity in the thickness of the oxide film and the composition of the metal.